وَلِلَّهِ مَا فِي السَّمَاوَاتِ وَمَا فِي الْأَرْضِ لِيَجْزِيَ الَّذِينَ أَسَاءُوا بِمَا عَمِلُوا وَيَجْزِيَ الَّذِينَ أَحْسَنُوا بِالْحُسْنَى ﴿۳۱﴾ الَّذِينَ يَجْتَنِبُونَ كَبَائِرَ الْإِثْمِ وَالْفَوَاحِشَ إِلَّا اللَّمَمَ إِنَّ رَبَّكَ وَاسِعُ الْمَغْفِرَةِ هُوَ أَعْلَمُ بِكُمْ إِذْ أَنْشَأَكُمْ مِنَ الْأَرْضِ وَإِذْ أَنْتُمْ أَجِنَّةٌ فِي بُطُونِ أُمَّهَاتِكُمْ فَلَا تُزَكُّوا أَنْفُسَكُمْ هُوَ أَعْلَمُ بِمَنِ اتَّقَى ﴿۳۲﴾

﴾31﴿ Wa lillaahi maa fis samaawaati wa maa fil ardi liyajziyal lazeena asaaa'oo bimaa 'amiloo wa yajziyal lazeena ahsanoo bilhusnaa
﴾32﴿ Allazeena yajtaniboona kabaaa'iral ismi walfawaa hisha illal lamam; inna rabbaka waasi'ul maghfirah; huwa a'lamu bikum iz ansha akum minal ardi wa iz antum ajinnatun fee butooni umma haatikum falaa tuzakkooo anfusakum huwa a'lamu bimanit taqaa

﴾31﴿ And to Allah alone belongs the choice of what is in the heavens and what is on the earth, so that Allah may recompense those who did evil for their deeds and reward those who did good with a good reward
﴾32﴿ They are those who avoid major sins and open immorality, except for minor slips. Indeed, your Lord is vast in forgiveness. He knows you best when He brought you forth from the earth and when you were hidden in the wombs of your mothers. So do not praise yourselves; He knows best who is truly righteous

[31,32] That is, the outcome and conclusion of the two mentioned qualities is that Allah, the Most High, will judge each group with justice and fairness, giving them a reward or punishment appropriate to their deeds. In this verse, both groups are mentioned.
(كَبَائِرَ الْإِثْمِ وَالْفَوَاحِشَ) — both are major sins, but the difference between them lies in their nature:
Kabāʾir al-ithm (major sins) are those forbidden in the Qur’an and Sunnah, with either a worldly or Hereafter punishment mentioned, even if the intellect or pure nature does not find them repulsive — like forms of shirk and major innovations.
The meaning of al-fawāḥish (indecencies) is that which all people of sound mind and pure nature detest, and which are also prohibited in the religion — such as adultery, lying, slander, violating the rights of others, oppressing people, etc.
(إِلَّا اللَّمَمَ) — there are three interpretations of this phrase:
1. That it includes all sins, whether minor or major, except for shirk and disbelief — on the condition that a person commits them once, then repents and does not return to them. This refers to those other than the prophets, because the prophets (peace be upon them) are protected from committing any kind of sin.
2. That it refers to minor sins — those for which no specific punishment or legal penalty is mentioned in the Qur’an or hadith, and which are pardoned through good deeds.
3. That it refers to passing thoughts in the heart — involuntary whispers or ideas that occur internally but are not acted upon.
According to the context of hadith, this last interpretation includes even the prophets (peace be upon them), based on the report in which this verse was recited along with the related poetic verse.
"If You forgive, O Allah, then forgive abundantly,
And which of Your servants has not erred at least a little?"
And when a person does not know the outcome of his own state, then فَلَا تُزَكُّوا أَنْفُسَكُمْ — do not declare yourselves as pure.
Do not describe your own soul by saying: “I am a person of high status,” or “I am destined for Paradise.”
Such self-praise and claims are forbidden.